Drafting instrument



NW. 12, 1946. Y H. BROWN 2,410,864

DRAFTING INSTRUMEN'I Filed May 15, 1944 ifa rold B 7 ffifadu;

Patented Nov. 12, 1946 UNITED'V'STATEJS PATENT -DRAFG INSTRUMENT I s H Q dBrown, Denver, 0010. Application May s, 1944, Serial No. 535,715

My invention relates to a drafting instrument and my object is to provide an eflicient low cost instrument of this character which may be employed to advantage by architectural and mechanical draftsmen, designers, artists, teachers, students and others having use for an instrument of this character.

The primary object of the invention is the provision of a drafting instrument whereby ,the aid of which cross-hatching and surface shading can be uniformly and expeditiously accomplished by a novice as accurately as by the most experienced draftsman.

A further object is the provision of an instrument of this character which may be used as a parallel ruler, compass, protractor, letter spacer and in drafting hexagonal and other geometrical figures,

Another object is the provision of a simple and inexpensive drafting instrument of this character which can be manufactured from cardboard, plastics and other suitable materials at low cost.

Other objects will hereinafter appear and in order that the invention may be fully understood reference will now be had to the accompanying drawing, in which:

Fig. 1 is a front elevation of one form of the instrument.

Fig. 2 is a cross section on line 22 of Fig. 1.

Figs. 3 and 4 illustrate modifications of the instrument.

Referring more particularly to the form disclosed by Figs. 1 and 2,2 designates an outer rectangular member comprising front and rear sides 4 and 6, respectively, and end members 8, which latter unite the former. The outer rectangular member 2 has a rectangular opening H1 in which an inner member I2 is movably arranged. The inner member I2 is held in assembly with the outer member 2 by slides M which are secured to the inner member and project into grooves [6 in the respective end members 8.

The inner member I2 is provided at its forward portion with a strip 18 adapted to be adjusted forward or backward relatively to the rear edge of the front side 6 to vary the spacing between cross-hatching or other parallel lines of a drawing. The strip I8 is secured in any of its adjusted positions upon the member l2 by any suitable means, such, for example, as screws 20 and thumb-nuts 22, which latter are threaded upon the former. The screws 20 are fixed to the member 12 and extend through slots 24 in the adjustable strip 18 to permit forward or, backward adjustment thereof, as above stated. The

2 Claims. (01. 33-410) 2 I. screws 20 also extend through the sudes wm secure the latter to the inner member-l2. The inner member I2 and the strip l8 have reduced overlapping portions which -cooperate 'with the screws 20 and thumb-nuts 22 in holding the member I2 and the strip I8 in assembly; The front side of the rectangular member 2 is beveledas indicated at 26 toprovide a ruler edge 30 for gui-ding the point of apencil or ruling pen' 'u'sedin drawing the cross-hatching or other parallel lines.

Operation-In using the instrument the desired spacing between cross-hatching or other parallel lines to be drawn may be obtained by moving the inner member [2 backward against the front edge 34 of the rear side 6 of the outer member 2. The thumb-nuts 22 are then loosened and the adjustable strip I8 is moved backward from the rear edge 36 of the front side 4 a distance equal to the desired spacing of the lines.

The thumb-nuts 22 are then tightened to firmly secure the adjustable strip l8 from independent movement upon the inner member l2. The outer member 2 is now moved backward until the edge 36 contacts the frontedge 32 of strip [8. The initial line is then drawn by moving a pencil or pen along the front edge 30 of the outer member 2. Spacing for the second line is then obtained by moving the inner member l2 backward against the edge 34 of the outer member 2 and then moving the latter backward until its edge 36 contacts the front edge 32 of the strip l8. Equal spacing for additional lines is obtained by repeating the foregoing operations. If preferred the adjustable stri l8, or its equivalent, may be applied to the outer member 2 and arranged to project into the path of the member l2 to check independent movement of the inner and outer members when being operated as above described.

In the form disclosed by Fig. 3, parts similar to those disclosed by Figs. 1 and 2, have been correspondingly numbered with the addition of exponents a. The slides l4, grooves l6, adjustable strip 18, screws 20 and thumb-nuts 22 have been dispensed with and onespacing of lines to be drawn is obtained by making the inner member l2a narrower than the opening Illa in the outer member 2a to leave a space 3 which determines the spacing between lines when the outer and inner members 2a and I2a, respectively, are operated in the same manner as the members 2 and I2. In order to obtain greater spacing between lines the movable element Hat is made shorter than the opening |0a to leave a space 5 which is wider than the space 3. For convenience of the draftsman this device may be equipped with various accessories which are optional with the manufacturer. In the present instance I have shown accessories comprising a scale 38, a protractor 40, geometrical figures 42, 44 nd 46, and perforations 48 for insertion of a pencil point whereby dots may be made from which guide lines may be drawn for letters and numbers to be drawn on an underlying sheet of paper.

The form disclosed by Fig. 4 comprises outer and inner members 21) and 12b, respectively, provided with edges extending at angles of various degrees. Additional angles are provided by the edges surrounding triangular openings 50 and 52 formed in the outer and inner members 2b and I 2b, respectively.

From the foregoing description it is apparent that I have provided a drafting instrument possessing the advantages above pointed out, and while I have shown and described three different forms of the device I reserve all rights to such other forms and modifications thereof as fall within the scope of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A drafting instrument comprising an outer member having a marginal ruling edge and an opening, an inner member slidable in said opening to determine the spacing for cross-hatching 4 or other parallel lines and comprising two elements having reduced overlapping portions slidable on each other whereby the width of the inner member may be adjusted relatively to the opening in the outer member and thereby vary the spacing of the lines, manual means for securing the two elements in adjusted position, and slides on one member projecting into grooves in the companion member to operably hold the members in assembly,

2. A drafting instrument comprising an outer member having a marginal ruling edge and an opening, an inner member slidable in said opening to determine the spacing for cross-hatching or other parallel lines and comprising two elements having reduced overlapping portions slidable on each other whereby the width of the inner member may be adjusted relatively to the opening in the outer member and thereby vary the spacing of the lines, threaded means fixed in one element and projecting through parallel slots in the companion member, manual means threaded upon said threaded means to cooperate therewith in holding said elements in adjusted position, and means projecting from one member and slidable in grooves of the companion member to hold said members in assembly.

HAROLD BROWN. 

